大直径超长冲孔灌注桩竖向抗压承载特性原位测试研究  

In-situ test study on vertical compressive bearing capacity characteristic of large diameter super-long impact-cone concrete pile

作　　者：闫楠[1,2] 白晓宇[3] 水伟厚 张明义[3] 廖天辉 

机构地区：[1]中国海洋大学海洋环境与生态教育部重点实验室,山东青岛266100 [2]中国海洋大学环境科学与工程学院,山东青岛266100 [3]青岛理工大学土木工程学院,山东青岛266033 [4]现代建筑设计集团上海申元岩土工程有限公司,上海200040 [5]青岛鼎林置业有限公司,山东青岛266555

出　　处：《中南大学学报（自然科学版）》2015年第7期2571-2580,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51078196);教育部高等学校博士学科点专项科研基金资助项目(20093721110002)~~

摘　　要：以广东某石油仓储工程为依托,通过8 MN·m能级强夯处理陆域回填区和海域回填区,对陆域试夯区和海域试夯区分别进行3根超长冲孔灌注桩单桩竖向抗压大吨位载荷试验及桩身力学测试。根据超长冲孔灌注桩实测数据探讨超长灌注桩的荷载传递机理和竖向承载特性。研究结果表明：试桩荷载-沉降（Q-s）曲线为缓变型,桩顶残余沉降量均在49%以上,桩顶回弹率介于20.4%～50.6%之间;极限荷载作用下,6根试桩表现出摩擦桩或端承摩擦桩的特性,桩端承载力只占总荷载很小一部分,陆域3根试桩为6%～34%,海域3根试桩为16%～35%;桩侧摩阻力和桩端阻力的发挥具有异步性,荷载主要由桩侧摩阻力承担。经过强夯处理浅层地基,桩侧摩阻力峰值发生在桩体中上部或浅部土层,即距桩顶（0.14～0.47）倍桩长的位置;部分土层的极限侧摩阻力较现行规范提供的设计侧阻力偏大;海域试桩比陆域试桩桩端阻力发挥更充分。Based on the vertical static load test and mechanical test of three single piles of the land trial ramming area and three single piles of the sea trial ramming area of a petroleum storage project in Guangdong Province, through dynamic compaction of 8 MN.m was carded out for the land backfill area and sea backfill area. The load transfer mechanism and vertical load bearing behavior of the pile are discussed according to measured data of super-long impact-cone concrete pile. The results show that the Q-s curves of the testing piles are of slow change type, pile top residual settlement is over 49%, and pile top resilience rate between 20.4%-50.6%. Under the limit loads, the proportions of end resistance in total resistance are between 6%-34% of the land area, and the proportions of end resistance in total resistance are between 16%-35% of the sea area respectively, which proves that the six piles are of friction pile or end-support friction pile. Pile side friction and pile end resistance play with the asynchronous nature, loads mainly borne by the pile side friction. The pile shaft resistance peak occurs at the top of piles or shallow soil layer, namely from the top of the pile 0.14-0.47 times the length of the location after dynamic consolidation treatment of shallow foundation; part of ultimate side friction of soil layer are higher than the side friction value provided by the existing norms; testing piles of the sea area give fuller play to pile tip resistance than the land area.

关 键 词：超长冲孔灌注桩 静荷载试验 桩身轴力 桩侧摩阻力 桩端阻力 

分 类 号：TU437.1[建筑科学—岩土工程]